You probably know how hard it can be to get a teenager to reach for fruit instead of a can of soft drink.
Most parents hope it's doing their body some good, without thinking much about their mind. New Australian research suggests the two may be closer than many realize.
Eating one additional serving of fruit each day was linked to a 13% lower risk of developing depression symptoms in Australian teenagers over three years of high school. The same shift was linked to a 7% lower risk of anxiety.
The findings come from a study of more than 6,500 teenagers published in October 2026 in Child and Adolescent Mental Health.
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The link between what teenagers eat and how they feel has been debated for years. The hardest question has been direction. Does poor nutrition set off low mood, or do teenagers who already feel low simply eat differently?
How the researchers tested the diet mood link
Researchers at the University of Sydney Matilda Centre followed 6,537 students from 71 secondary schools in New South Wales, Queensland and Western Australia. The teens were about 12.5 years old at the start.
They answered annual surveys about their diet and their mood from Year 7 through Year 10. Crucially, the team excluded anyone who already met the threshold for depression or anxiety at the start.
That left a group whose mental health could change over time. Researchers could then watch which habits came before any symptoms appeared, rather than the reverse.
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Lead author Dr Lily Davidson said in the Sydney announcement that high school is a stretch of growing independence over food and drink. It is also when many mental health problems first emerge.
Sugary drinks moved the dial the other way
The pattern reversed for sugar-sweetened drinks. Teenagers who drank more soft drinks, cordials and sports drinks had a higher risk of both depression and anxiety symptoms. The link to anxiety was stronger in boys.
Average fruit intake in the study was about two to two and a half servings a day. One more could tip the balance.
Davidson was careful to note that no one is saying an apple will prevent depression, or that a soft drink will trigger anxiety. Mental health is more complex than that, and the study is observational, not a trial that can prove cause and effect.
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Her argument is that diet is one of the few parts of a teenager's life that can realistically be changed. That is why the researchers want it treated as part of mental health prevention.
For most teenagers, the practical shift is small. One extra piece of fruit at breakfast, or a swap from a sugary drink to water at lunch, is enough to match the daily difference the researchers measured.
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This article is made and published by Ida-Marie Palm Varbæk, who may have used AI in the preparation.